Miniature radial motor



Jan. 7, 1941. A. M. TRIPP 2,228,187

MINIATURE RADIAL MOTOR Filed April 9, 1940 2 Sheegs-Sheet 1 Jan. 7, A M. T p 2,228,187

I MINIATURE RA DIAL MOTOR Filed April 9, 1940 2 Sheets-Sheet 2 Patented Jan. 7, 1941 UNITED STATES PATENT OFFICE 8 Claims.

My invention consists in new and useful improvements in a miniature fluid operated'motor primarily for use in connection with toys such as airplanes, boats, and other'power-driven devices.

The principal object of my invention is to provide a radial motor of this type which is constructed essentially of seamless drawn tubing and having a. minimum of working parts.

Another object of the invention is to provide a radial motor which is extremely light and which may be economically constructed of stock parts which are easily assembled.

A further object of the invention lies in the construction and arrangement of the piston connecting ro'ds so as to eliminate friction and facilitate alignment in operation.

A still further object of my invention is to provide a fluid operated motor of this type wherein the operating parts are so designed and constructed as to be readily accessible for replacement and lubrication.

With the above and other objects in View which will appear as the description proceed-s, my invention resides in the novel features hereinafter set forth, illustrated in the accompanying drawings .and more particularly pointed out in the appended claims.

Referring to the drawings in which numerals of like character designate similar parts throughout the several views,

Fig. 1 is a front elevation of a four-cylinder radial motor constructed in accordance with my invention. 7

Fig. 2 is a sectional View taken on line 2-2 of Fig. 1.

Fig. 3 is a transverse section showing the motor advanced 45 from the position shown in Fig. 2, and

Fig. 4 is an exploded perspective view of the valve and cylinder mounting assembly.

In the drawings, I represents a longitudinally extending hollow supporting shaft formed preferably of thin drawn seamless tubing, suitably connected at one end'to a fluid inlet coupling 2 leading to a source of fluid supply not shown. Adjacent the opposite end, this hollow shaft I is provided with opposed radial ports 3 and 4 adapted to register with corresponding ports in a valve port separator 5 which is inserted through the open end of the shaft I as clearly shown in Fig. 2. The valve separator 5 is also constructed of drawn seamless tubing, and as shown in detail in Fig. 4, consists of a tubular b'odyportion 6 open at one end to provide an exhaust port I and adapted to fit snugly within the end of the hollow shaft I. The opposite end of the separator 5 is closed and one side of the body 6 is provided with an opening 8 adapted to legister with the port 4 in the hollow shaft I to 6 form a cylinder exhaust port. The opposite side of the body 6 is indented as at 9 to provide a channel leading to the port 3 in the hollow shaft I which serves as a cylinder intake port.

Rotatable about the hollow shaft I is a Cy-10 lin-drical sleeve I0 which, in the form of my invention shown in the drawings, abuts the coupling 2 at one end which acts as a longitudinal stop, the other end of the said sleeve terminating a slight distance short of the adjacent front end '15 of the hollow shaft I. This front end of hollow shaft I is preferably turned outwardly to form an annular retaining lip II for a cam disc I2 eccentrically mounted on the shaft I through the medium of an opening I3. The disc I2 is thus interposed between the retaining lip M of the hollow shait I and the adjacent extremity of the sleeve I B, being rigidly secured to the supporting shaft I by any suitable means such 7 as soldering or welding. 25

In radial alignment with the ports 3 and 4 in hollow shaft I, the rotatable sleeve I0 is provided with a. series of radially projecting nipples I4 .by means of which respective cylinders I5a, I 5b, I50, and I5d are mounted on the sleeve I0. Each of these cylinders is formed of seamless drawn tubing and consists of an elongated cylindrical body open at its outer end to permit the insertion of respective pistons Ilia, I61), I60, and id, said cylinders being closed at their inner ends except for suitable "openings to receive respective nipples I4 on the sleeve I0. As will be seen from Fig. 2, .the end openings in the cylinders are arranged off-center whereby the longitudinal axes of the cylinders are disposed slightly forwardly of the ports 3 and 4, for the purpose hereinafter set forth.

In Fig. 4 I have shown the nipples I4 on the sleeve I0 prior to the mounting of the cylinders thereon. Referring to Fig. 2, it will be seen that after the cylinders are in place on the sleeve Ill, each of the nipples I 4 is crimped against the bottom ofrthe cylinder to rigidly secure the same in place. This crimping may be performed in any suitable manner such as with a crimping punch, and in order to insure a perfectly sealed joint, the cylinders may be either soldered or welded to the sleeve I0.

Each of the pistons Ilia to IBd consists of an elongated cylindrical member of drawn seamless tubing closed at its inner end and of slightly less diameter than that of the cylinders so as to permit said pistons to freely reciprocate with-in respective cylinders, yet maintaining a closeness of fit which will prevent leakage of the operating fiuid. In other words, all of the telescoping parts of my improved motor are constructed with diameters and thickness of walls held to such close limits of tolerance as to permit movement of one within the other without leakage on the one hand, or undue friction on the other.

Ila, 11b, I10, and H11 represent connecting rods for the pistons Ito to ltd, respectively, each of which preferably consists of a strip of relatively thin light metal stamped to form a longitudinal stiffening rib I8. One end of each rod is bent substantially in a U-shape --to form a connecting hook I9, the free extremity of which lies within the open end of respective pistons and is pivotally connected thereto by means of a transverse pin 26 which extends through aligned openings in the walls of the piston and both legs of the U-shaped connecting hook NJ.

The opposite ends of these connecting rods are provided with openings to receive a common crank pin 2| fixed to the cam disc l2 and pro jecting outwardly therefrom. In order to minimize friction with the disc I2, I preferably provide a suitable spacing member 22 either in. the form of a washer or a shoulder on the crank pin 2 I said spacer lying between the innermost connecting rod and the outer face of the disc. A second washer 23 and cotter pin 24 may be provided at the outer end of the crank pin to retain the connecting rods in place thereon.

The rotatable sleeve It is provided intermediate its ends with any suitable power take-off, that shown in Fig. 2 of the drawings consisting of a pulley 25 over which a belt 26 is adapted to run. It is to be noted, however, that in place of this power take-off, I may mount a propeller on the sleeve H) whereby the motor may be installed in a toy airplane or toy boat.

Having thus described the construction and assembly of my improved radial motor, its operation is as follows:

By means of the coupling 2, the hollow shaft l is connected to any suitable source of fluid supply such for example as a tank of compressed air, or inert gas under pressure, or to a source of steam pressure. In the form shown in the drawings, the coupling 2 serves as the sole mounting for the hollow shaft I and is provided with threads 2a to facilitate the connection to said source of supply. Either the coupling 2 or the source to which it is connected may be provided with any convenient valve means (not shown) for controlling the flow of pressure fluid to the motor.

The tubular shaft I conveys the operating pressure either in the form of air, gas, or steam, from the source of supply to the intake valve port 3 in the Wall of the shaft I, the outer end of said shaft being closed by the valve separator 5.

Following one complete cycle of a given cylinder and assuming that the parts are in the positions shown in Fig. 3, the fluid pressure introduced through the hollow shaft lenters the cylinder Ilia through port 3 which in this position is in full register with the opening in the nipple I4 of that cylinder. In order to more clearly follow the cycle of the cylinders, I have designated the different positions thereof by lines A to I, inclusive, on Fig. 3. The fluid pressure entering cylinder 15a forces piston 16a outwardly and as this piston is connected to the eccentrically disposed crank pin 2| which is stationary on the fixed shaft I, this outward movement of the piston causes the entire motor, including the mounting sleeve II], to rotate on the hollow shaft l in the direction of the arrow (Fig. 3).

When the cylinder 15a passes the position indicated by line B, its intake port closes but due to the rotation of the entire motor, the cylinder 15d has reached the position indicated by line I at which point its intake port has begun to open, thereby causing pressure fluid to enter the cylinder lBd to force piston lBd outwardly, continuing the rotation of the motor.

During this rotation, the piston I6a has continued to move outwardly in cylinder l5a and by the timethis cylinder reaches the position indicated by line C, the intake valve of cylinder [5d has reached position A and is fully open. As the motor continues to rotate by the force of the fluid in cylinder l5d, cylinder [50. reaches position D at which point its piston 16a has reached its extreme outward position and its nipple It has begun to register with the exhaust port 4, exhausting the fluid pressure to atmosphere through the open end I of the valve separator 5. The exhausting of the fluid pressure in cylinder l5a continues until said cylinder has reached the position H when it becomes fully closed, the piston 16a having returned to the extremity of its inward stroke. When the cylinder [5a reaches position I, its nipple starts to register with the inlet port 3 and the cycle just described is repeated.

It naturally follows that the cycle of each cylinder is successively the same as that just described, it being noted that the exhaust registration is maintained for substantially one-half of the cycle, whereby compression of the fluid in the cylinders is avoided, and the full benefit of the pressure fluid on the active cylinders is made available.

As heretofore pointed out, my improved motor has been designed primarily as a miniature motor for use in connection with the operation of power-driven toys and one of its outstanding advantages lies in its extreme lightness which is of particular importance when the motor is to be used on toy airplanes, for example. The construction of this motor from very light seamless tubing makes available a maximum pressure surface in the cylinders with a minimum of weight and in practice I have found that due to this lightness of structure, any gyroscopic action set up by the revolution'of the cylinders is negligible.

Another important feature in the design of this motor lies in the self-alignment of the connecting rods Without the necessity of guides. Due to the fact that the pins extend entirely through both walls of the pistons and through both legs of the U-shaped connecting hooks [9, the outer ends of the connecting rods are permitted freedom of movement transversely of the pistons as well as pivotally on the pins 20.

Furthermore, due to the off-center mounting of the cylinders on the rotary sleeve I0, as clearly shown in Fig. 2, forward tipping action of the cylinders is prevented.

Finally, it is to be noted that by constructing all telescoping and relatively movable parts of my improved radial motor of drawn seamless tubing, I am ableto produce an eflicient miniature motor without the necessity of machining these parts, thus facilitating the economical construction of toy motors.

While I have described and illustrated the motor as being rotatable about a fixed hollow stationary shaft I carrying a fixed crank disc l2, it will be apparent that the same principle of operation may be followed with the cylinders and sleeve [0 stationary and the hollow shaft l with its crank disc I2 rotatable in the sleeve, in which event the power take-off would be connected to the hollow shaft I.

From the foregoing it isbelieved that the construction and operation of my invention may be readily understood by those skilled in the art without further description, it being born-e in mind that numerous changes may be made in the details disclosed without departing from the spirit of my invention as set out in the following claims.

What I claim and desire to secure by Letters Patent is:

1. In a miniature radial motor, a tubular shaft, valve means in said shaft, a supporting sleeve surrounding said'shaft, a series of radial cylinders carried by said sleeve in communication with said valve means, and pistons in said cylinders, all of said parts being constructed essentially of seamless drawn tubing.

2. A miniature radial motor comprising a tubular shaft member having radial openings forming an intake and an exhaust port therein, means separating said ports, a crank arm fixed to one end of said shaft member, means connecting the other end of said shaft member to a source of fluid pressure, a tubular sleeve member embracing said shaft member and provided with a plurality of radial openings in alignment with said ports, one of said members being rotatable with respect to the other, tubular cylinders mounted radially on said sleeve member in communication with respective radial openings, tubular pistons adapted to reciprocate in respective cylinders, and means connecting the outer ends of said pistons to said crank arm.

3. In a miniature radial motor including a supporting shaft, a crank arm on said shaft, a series of ra'dially disposed cylinders rotatably mounted on said shaft, and pistons reciprocably mounted in said cylinders; self-aligning means connecting said pistons to said crank arm, comprising connecting rods rotatably secured at one end to said crank arm, connecting heads at the opposite ends of said connecting rods, and means at the outer ends of said piston-s rotatably and slidably connected to respective heads.

4. In a miniature radial motor including a supporting shaft, a crank arm on said shaft, a series of radially disposed cylinders rotatably mounted on said shaft, and open-ended pistons reciprocably mounted in said cylinders; self-aligning means connecting said pistons to said crank arm, comprising connecting rods having substantially hook-shaped outer ends terminating within the confines of respective pistons, a transverse pin extending through aligned openings in the walls of each piston and both legs of respective hookshaped ends, whereby said connecting rods are capable of both pivotal and longitudinal movements on said pins, the opposite ends of said connecting rods being rotatably mounted on said crank arm.

5. A miniature radial motor comprising a tubular shaft having radial openings forming an intake and an exhaust port therein, means separating said ports, a crank arm fixed to one end of said shaft, means connecting the other end of said shaft to a source of fluid pressure, a tubular sleeve rotatably embracing said shaft and provided with a plurality of radial openings in alignment with said ports, a radially extending nipple surrounding each of said radial openings, a series of radial tubular cylinders closed at their inner ends, openings in the closed ends of said cylinders embracing respective nipples on said sleeve, means securing said cylinders on said sleeve about said nipples, tubular pistons adapted to reciprocate in respective cylinders, and means connecting the outer ends of said pistons to said crank arm.

6. A miniature radial motor comprising a tubular shaft having radial openings forming an intake and an exhaust port therein, means separating said ports, a crank arm fixed to one end of said shaft, means connecting the other end of said shaft to a source of fluid pressure, a tubular sleeve rotatably embracing said shaft and provided with a plurality of radial openings in alignment with said ports, a radially extending nipple surrounding each of said radial openings, a series of radial tubular cylinders closed at their inner ends, openings in the closed ends of said cylinders embracing respective nipples on said sleeve, means securing said cylinders on said sleeve about said nipples, tubular pistons adapted to reciprocate in respective cylinders, and a series of external connecting rods rotatably secured at their inner ends to said crank arm, and at their outer ends to respective pistons.

7. A miniature motor as claimed in claim 6 wherein the openings in the closed ends of said cylinders are eccentrically disposed, whereby the axes of said cylinders lie forwardly of the axes of said nipples, to compensate for the forward pull of said connecting rods on said cylinders.

8. A miniature motor as claimed in claim 6 wherein the outer ends of said nipples are crimped over the closed ends of said cylinders to form securing means for the latter.

ARTHUR M. TRIPP. 

